Bucket-wheel for turbines.



PATENTED JULY 28, 1908.

No. 894,659. s

, E. KALLBBRG.

BUCKET WHEEL FOR TURBINES.

APPLIQATION FILED DBO. 29,1906.

Witnesses:

. Bucketheels-for Turbines, following is. a-specification.

To all whom itjrmi concern:

. PA T OFFICE Ea s'r' K' LLBERdoF BERLINQGERMANY,ASSIGNOR TO GENERAL: ELECTRIC COMPANY a AGORPORATION OF-NEWVYORK. u 1 9 BUCKET-WHEEL ronrunnmns.

1a., seaebe;

Beit knownthat I, -,Ea 1\rs'r K L'L'BERG, a sub ect of the Emperor of Austria-Hungary, residtng'at Berlin, Germany, have invented certain new and useful Improvements in of the 1 The present invention relates to theconstructlon of bucket Wheels for turbines and -,.more especially to those intended to be operatedat high bucket ,slpeeds.

1 groove of dove-ta 'arrangedto receive thebases-of individual buckets mounted thereon.- -of" ins ertingthe buckets into the groove an axially extending filling recess is provided that cuts away a certain from one side of the rim, which recess is Certain types of buc I am famlhar are provided with 'a peripheral 1 or T-sliaped cross section For the purpose section of metal large' enough to permit the' insertion of a I bucket base and is of a depth (the same or are such that cutting the substantiaily the same as that of the groove. I have discovered that the internal stresses in the metal of which the H filling recess in the rim of the wheel throws the latter out of true, no matter how true-it may have been before. This is more noticeable when the wheel is mnnm and is particularly objece rotating bucketstravel at parts by a clearance; of only a few hundredths of an inch. I have discovered that thisobjectionable distortion of wheel can be obviated by making a thin th tiiialif'row slot in the side of the rim oppositethe mg recess. I prefer to make as many of these slots as there are filling recesses. When thewheel 1s lar e the number of filling recesses and there ore of these narrow slots isgreater than where the wheel is small. In the accompanying drawing, which illustra'tes one of the embodiments of my inven- .a-rim 20f suitable section and containing a tion, Figure 1 is a view in elevation of a part of a wheel; Fig. 2 IS an aX1alsect1on;F1g. 3 1s a plan view of apart of the wheel; and Fig. 4

is a perspective of a locking bucket or filling p ece, h

1 represents the web of the wheel having V groove 3 arranged to receive the bases '4 of the buckets 5. I The groove 3 may have any suitable sha e, as'for examplea dove-tail or TI -shape. T e latter shape is preferable since a wheels. with which wheel is composed;

' Patented July as, 1908.

there will be no horizontal componenttend-- ing to spread the sides of the rim when the wheel-is revolving. The ends of the buckets "may or may notbe'provided with a'cover 6 .as desired. "I find 'it desirable, when acover is used, to secure lt'in place by means of tenons 7 formed integralwiththe endrmfthe.

buckets, and whichpi'oject through the cover and are riveted over at the ends.

tenons or more as desired. In order touintroducethebuckets. intothe groove 3, an axially extending recess is'provided having the same shape in elevation as the base of the locking buckets. t Referring to' Fig. 4, 8 represents'the base of the lockin bucket,-.wh1ch is of awidth' Each bucket may be provided with one of these sufficient to'c ose fthe recess, and is provided with lugs '9 and 10 on opposite sides that eni gage shoulders 11 and 12 formed in the side .walls of the-recess. 13 indicates a shoulder formed on the base of the lockin bucklet' that engages with and is' secure b shoulder forming. a part of the T-s aped bucket-receiving groove. In the side of the wheel rim opposite to the recess is a thin,

narrow slot 14, the object of which is to neuv tralize' the effects of internal stresses in the rimoccasioned by the cutting of the recess. The dimensions of the slot 14 canv be varied 'to'suit the requirements. Ingeneral practice I have found that it is satisfactory to form this slot with an ordinary saw or mi ling cutter and of a depth the sameor substantially the same as that of the filling recess. By actual test I have demonstrated that, no matter how much the wheel is out of true after the recess is made, it will be brought back to true just as soon as the thin slots 14 are cut, and will remain true at the speed at which it is normally intended to run.

I have shown my invention in connection with a wheel having buckets .provided with a fairly large base so that the base of onebucket engages with that of another, and the two act as separators to maintain the pitch distance of the buckets. this arrangement, form the T o'r'dove-tall directly on the bucket itself, and between each two buckets insert a s ace-block of suitable shape that is retained y the walls of the T- shaped or other roove. v

The piece for filling the recess is shown as forming a part of one of the buckets, but itis evident that I may make the filling piece I may, instead of.

or pieces separate from the bucket or buckets. It is also evident that I may change the position of the slot or slots to equalize the internal stresses to suit the requirements.

The locking bncketor filling piece is prevented from working out by the screw 15, the threads of which engage those in the filling piece and also those in the rim.

n accordance with the provisions of the patent statutes, 1 have described the principle of operation of my invention, together with the a paratus which I now consider to re resent t 1e best embodiment thereof; but

1 esire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

W'hat I claim as new and desire to secure by Letters Patent of the'United States, is,

1. A turbine wheel having a bucket-receiving groove, a recess through which buckets are inserted into the groove, buckets mounted in the groove and retained therein, and a slot of less width than the recess for equalizing the stresses in the wheel caused by the formation of the recess.

2. A turbine wheel having a bucketreceiving nd retaining groove of suitable cross- 8601011, one or more recesses in the side of the wheel rim through which the buckets are inserted into the groove, buckets niountedin the groove, a filling means for said recess, and one or more slots having parallel sides formed in the rim on the side opposite the said recess or recesses for equalizing the stresses in the wheel caused by the formation of the said recess or recesses.

3. A'turbine wheel having a bucket-receiving groove, a lateral recess through which the buckets are inserted, and a slot of less width than the recess located opposite it to relieve the stresses 1n the wheel, buckets mounted in the groove and retained by the walls thereof, and a means for filling the recess.

4. A turbine wheel having a rim with a bucket-receiving groove, a lateral recess through which the bases of the buckets are inserted into the groove, and a slot of less width than the recess to relieve the stresses in the rim, buckets, bases for the buckets which are situated in the groove and retained by the walls thereof, and a locking means for the buckets which fills said recess.

5. A turbine wheel having a rim with a bucket-receivin groove, a filling recess; and a narrow slot aving parallel sides to re lieve stresses in the rim, buckets mounted in the groove, a filling or locking piece for closing the recess, and interlocking shoulders between the said piece and the wheel rim for retaining the piece against centrifugal force.

6. A turbine wheel having a rim with a bucket-receiving groove, a filling recess, and

a slot to relieve stresses in the rim, buckets mounted in the groove, a filling or locking piece for closing the recess, a shoulder between a side of the said piece and the rim,

I and a shoulder between the end of the piece and the wall of the groove, the said shou ders cooperating to secure the locking piece against centrifugal strains.

7. A turbine wheel having a rim provided with a groove for receiving the bases of the buckets, a recess in one side of the rim through which the bases of the buckets are inserted into the groove, a slot in the oppol site sideof the rim to relieve stresses therein, and a filling or locking piece which is inserted in the recess and extends across the groove into engagement with the side thereof opposite said recess.

8. A turbine wheel having a rim provided with an undercut groove for receiving the bases of the buckets, a recess in one side of the rim through which the bases of the buckets are inserted into the move, .a narrow slot having parallel sides located in the opposite side of the rim to relieve stresses in said rim, and a locking piece in the recess which extends across the groove into engagement with the overhanging side wall thereof opposite said recess.

9. A turbine wheel having a rim provided with an undercut groove for receiving the bases of the buckets, a lateral-recess through which the bases of the buckets are inserted into the groove, a slot in the rim opposite the recess to relieve stresses in said rim, and a locking piece which engages the walls of the recess and extends across the groove into engagement with the overhanging wall thereof adjacent said slot.

In witness whereof, I have hereunto set my hand this 4th day of December, 1906.

ERNST KALLBERG.

Witnesses:

JULIUs RUMLAND, ALFRED WOLF. 

